<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>选择器</title>
    <style>
        p{
            color: green;
        }

        #d1{
            color: red;
        }
        #d2{
            color: red;
        }
        #d3{
            color: red;
        }

        .hi{
            color: blue;
        }
    </style>
</head>
<body>
<p>过去岁月不可追</p>
<p id="d2">未来日子你别催</p>
<p>莫愁身外七八事</p>
<p>且尽眼前三两杯</p>
<div>你好</div>
<div id="d3">你好</div>
<div>你好</div>

<h1 class="hi">李白</h1>
<p class="hi" id="d1">将近酒，杯莫停</p>
<div class="hi">窗前明月光</div>
</body>
</html>